And I use addRosterElement() to add elements to the data store. This model needs to work with children and there is my problem. I need to add/remove children dynamically acording to some checkboxes (per instance), so I should notify the model about it. I can add a method like addChildrenToItem(RosterElement *element) in Roster class, but then I would have to look for the QModelIndex for that row, which means I have to iterate over the whole data store.